Feeding our gut microbiota

We are made of more bacterial than human cells: bacteria that colonize our body reach their highest density in the large intestine, where they form the so called ‘gut microbiota’.

All these microbes are fundamental for our health: they take part in digestion of fibre, control blood sugar, manage cholesterol, produce vitamins, control hormonal balance, compete with pathogens, regulate immune system, communicate with the brain and so much more.

The gut is the largest interface with external environment: the human microbiota continuously deals with the huge amount of food and substances introduced every day and which might represent a threat for the health. Furthermore, they have to take enough ‘nutrients’ for keeping them alive: not surprisingly, research shows that diet influences the composition of the gut microbiota and its functions.


Despite a lot of attention has been focused on the impact of macronutrients (carbohydrates, lipids, proteins) on the gut microbiota composition, less consideration is given to micronutrients, vitamins and minerals. Tracing the roles and impacts of trace elements on the gut microbiota and microbiome (i.e. the microbiota’s genome) is the goal of my research.

What we know about minerals and trace elements

Minerals are inorganic substances required by the body for several functions, from formation of teeth and bones, to constituents of enzymes . We require different amounts of each mineral; people have different requirements, according to their age, sex, physiological state and sometimes their state of health. The Department of Health has published Dietary Reference Values (DRVs) for minerals for different groups of healthy people.

Trace elements are mineral required in very low amount in human body: essential trace elements for human body are iodine, zinc, selenium, copper, molybdenum, chromium, cobalt, iron; also manganese, silicon, nickel, boron, vanadium might play important roles for the health. Potential toxic trace elements occasionally introduced with diet exist as well (e.g. lead, cadmium, mercury, arsenic, aluminium, lithium).

Micronutrients deficiencies negatively impact the microbiota: populations at risk for some specific mineral shortage, such as elderly, have been found to have a poorer microbiota in term of richness and diversity respect to groups of population that follow a varied and balanced diet. Evidence is supported by the fact that bacteria needs some essential mineral for their survival, for instance iron, zinc or selenium. Indeed, they have developed sophisticated transport-mechanisms in order to guarantee the adequate amount of the essential element during sort-term shortage conditions, but also to avoid the uptake of an excessive amount which is generally toxic for bacteria. Also the repetitive introduction of excessive amount of mineral, especially toxic trace elements, negatively affect the gut microbiota composition.

Therefore, essential trace elements are important for keeping us healthy…directly, playing several roles in human eukaryotic cells, but also indirectly, as ‘nutrient’ for our bacteria.

How to avoid any mineral deficiency?

Nature has wisely provided us with a large amount of different food sources enriched in all the macro and micronutrients that we require for staying alive and healthy.

Recommendations for a healthy and balance diet

1. Drink at least 2 L of water per day: it is a great source of available minerals and trace elements

2. Eat 2 portions of vegetables and 3 of fruits per day, varying the type and the colour

3. Varying cooking methods: some minerals are lost after cooking, therefore alternating cooked and raw veg/fruits ensures an adequate amount of all the micronutrients

4. Respect, when possible, the seasonality of products: the less conserved veg and fruits are, the more minerals and vitamins they store

5. Prefer whole grains and cereals

6. Alternate protein sources during the week

7. Reduce the consumption of junk food (enriched in sugar and saturated fats)

8. Groups of population at risk for mineral deficiencies:

– Vegetarian/vegan people

– Elderly

– Pregnant women

The role of the dietician/nutritionist is essential for providing them all the specific recommendations for covering their requirements.

I really admire Nutritank’s aim of sharing nutrition pills among healthcare professionals and the public. Given the benefits that a healthy lifestyle and diet provide to human health, I am delighted to contribute to increase this awareness providing research-based evidence

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